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Small Construction Activity Waivers

The Construction General Permit allows a permittee to be waived from the requirement to apply for a permit in three limited circumstances. To be eligible for this waiver, you must certify to EPA that you are eligible for one of the following:

  • Rainfall Erosivity Waiver. The small construction site has a low predicted rainfall potential where the rainfall erosivity factor (R Factor) is less than 5 during the period of construction activity. The Rainfall Erosivity Factor waiver uses this factor to determine whether the potential for polluted discharge is low enough to justify a waiver from permit requirements. This waiver is time sensitive and is dependent on when during the year a construction activity takes place, how long it lasts, and the expected rainfall and intensity during that time. Use this online calculator or the Construction Rainfall Erosivity Waiver Fact Sheet (PDF) (13 pp, 1.81MB) for assistance in determining the R Factor for a particular small construction site. If your project is located in an area where EPA is the permitting authority, your project disturbs less than five acres, and your R factor is less than 5, you may submit a Low Erosivity Waiver Certification via EPA's eNOI system or complete and send to EPA by mail a paper Low Erosivity Waiver Certification form (PDF) (4 pp, 213K).

  • A determination that stormwater controls on the small construction site are not necessary based on an EPA established or approved Total Maximum Daily Load (TMDL) that addresses the pollutants of concern for construction activities (e.g., sediment). For more information, see Appendix C (PDF) (4 pp, 99K) or contact your state NPDES coordinator.
  • The Equivalent Analysis waiver is available for non-impaired waters only. The operator can develop an equivalent analysis that determines allocations for the small construction site for the pollutant(s) of concern or determines that such allocations are not needed to protect water quality. This waiver requires a small construction operator to develop an equivalent analysis based on existing in-stream concentrations, expected growth in pollutant concentrations from all sources, and a margin of safety.
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Last updated on March 19, 2012 4:30 PM
URL:http://cfpub2.epa.gov/npdes/stormwater/waiver.cfm